1. Field of the Invention
The present invention relates to a filter aid for analytical use and method for preparing the same, more particularly, a filter aid for analytical use consisting essentially of tangled short-length ceramic fibers having a bulk density in the range of about 0.02-0.18 g/cm.sup.3 and method for preparing the same.
2. Description of the Prior art
Quantification of crude fibers in the component analysis of foods and feeds has a significance in evaluating their nutritional components, as well as in evaluating unassimilable or scarcely assimilable components such as dietary fibers.
Conventionally, quantitative analysis of crude fibers is carried out as follows: A sample which has been accurately weighed is boiled in 1.25% aqueous sulfuric acid solution. The mixture is filtered and washed while it is hot. The residue is boiled together with a filter aid in 1.25% aqueous sodium hydroxide solution, and the resultant is filtered and washed while it is hot. The residue is dried together with a filter bed formed by the filter aid to give a constant weight. They are then incinerated to determine the loss, followed by calculating the percentage against the weight of the sample.
Usually, asbestos has been used as a filter aid.
Recently, it is found that asbestos is one of the substances which are responsible for the occurrence of lung cancer, and the replacement of the asbestos with ceramic fiber has been proposed (Chemical Engineering, Issue of June, pp. 526-531, 1977, and Kagaku Sochi, Issue of March, pp. 39-51, 1983).
Since a filter aid for analytical formed use of ceramic fiber has not been commercialized, analysts in the field have been expecting the development of such filter aid.